1 /* Postprocess module symbol versions 2 * 3 * Copyright 2003 Kai Germaschewski 4 * Copyright 2002-2004 Rusty Russell, IBM Corporation 5 * Copyright 2006 Sam Ravnborg 6 * Based in part on module-init-tools/depmod.c,file2alias 7 * 8 * This software may be used and distributed according to the terms 9 * of the GNU General Public License, incorporated herein by reference. 10 * 11 * Usage: modpost vmlinux module1.o module2.o ... 12 */ 13 14 #include <ctype.h> 15 #include "modpost.h" 16 17 /* Are we using CONFIG_MODVERSIONS? */ 18 int modversions = 0; 19 /* Warn about undefined symbols? (do so if we have vmlinux) */ 20 int have_vmlinux = 0; 21 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 22 static int all_versions = 0; 23 /* If we are modposting external module set to 1 */ 24 static int external_module = 0; 25 26 void fatal(const char *fmt, ...) 27 { 28 va_list arglist; 29 30 fprintf(stderr, "FATAL: "); 31 32 va_start(arglist, fmt); 33 vfprintf(stderr, fmt, arglist); 34 va_end(arglist); 35 36 exit(1); 37 } 38 39 void warn(const char *fmt, ...) 40 { 41 va_list arglist; 42 43 fprintf(stderr, "WARNING: "); 44 45 va_start(arglist, fmt); 46 vfprintf(stderr, fmt, arglist); 47 va_end(arglist); 48 } 49 50 static int is_vmlinux(const char *modname) 51 { 52 const char *myname; 53 54 if ((myname = strrchr(modname, '/'))) 55 myname++; 56 else 57 myname = modname; 58 59 return strcmp(myname, "vmlinux") == 0; 60 } 61 62 void *do_nofail(void *ptr, const char *expr) 63 { 64 if (!ptr) { 65 fatal("modpost: Memory allocation failure: %s.\n", expr); 66 } 67 return ptr; 68 } 69 70 /* A list of all modules we processed */ 71 72 static struct module *modules; 73 74 static struct module *find_module(char *modname) 75 { 76 struct module *mod; 77 78 for (mod = modules; mod; mod = mod->next) 79 if (strcmp(mod->name, modname) == 0) 80 break; 81 return mod; 82 } 83 84 static struct module *new_module(char *modname) 85 { 86 struct module *mod; 87 char *p, *s; 88 89 mod = NOFAIL(malloc(sizeof(*mod))); 90 memset(mod, 0, sizeof(*mod)); 91 p = NOFAIL(strdup(modname)); 92 93 /* strip trailing .o */ 94 if ((s = strrchr(p, '.')) != NULL) 95 if (strcmp(s, ".o") == 0) 96 *s = '\0'; 97 98 /* add to list */ 99 mod->name = p; 100 mod->next = modules; 101 modules = mod; 102 103 return mod; 104 } 105 106 /* A hash of all exported symbols, 107 * struct symbol is also used for lists of unresolved symbols */ 108 109 #define SYMBOL_HASH_SIZE 1024 110 111 struct symbol { 112 struct symbol *next; 113 struct module *module; 114 unsigned int crc; 115 int crc_valid; 116 unsigned int weak:1; 117 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 118 unsigned int kernel:1; /* 1 if symbol is from kernel 119 * (only for external modules) **/ 120 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */ 121 char name[0]; 122 }; 123 124 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 125 126 /* This is based on the hash agorithm from gdbm, via tdb */ 127 static inline unsigned int tdb_hash(const char *name) 128 { 129 unsigned value; /* Used to compute the hash value. */ 130 unsigned i; /* Used to cycle through random values. */ 131 132 /* Set the initial value from the key size. */ 133 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++) 134 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 135 136 return (1103515243 * value + 12345); 137 } 138 139 /** 140 * Allocate a new symbols for use in the hash of exported symbols or 141 * the list of unresolved symbols per module 142 **/ 143 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 144 struct symbol *next) 145 { 146 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 147 148 memset(s, 0, sizeof(*s)); 149 strcpy(s->name, name); 150 s->weak = weak; 151 s->next = next; 152 return s; 153 } 154 155 /* For the hash of exported symbols */ 156 static struct symbol *new_symbol(const char *name, struct module *module) 157 { 158 unsigned int hash; 159 struct symbol *new; 160 161 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 162 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 163 new->module = module; 164 return new; 165 } 166 167 static struct symbol *find_symbol(const char *name) 168 { 169 struct symbol *s; 170 171 /* For our purposes, .foo matches foo. PPC64 needs this. */ 172 if (name[0] == '.') 173 name++; 174 175 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) { 176 if (strcmp(s->name, name) == 0) 177 return s; 178 } 179 return NULL; 180 } 181 182 /** 183 * Add an exported symbol - it may have already been added without a 184 * CRC, in this case just update the CRC 185 **/ 186 static struct symbol *sym_add_exported(const char *name, struct module *mod) 187 { 188 struct symbol *s = find_symbol(name); 189 190 if (!s) { 191 s = new_symbol(name, mod); 192 } else { 193 if (!s->preloaded) { 194 warn("%s: '%s' exported twice. Previous export " 195 "was in %s%s\n", mod->name, name, 196 s->module->name, 197 is_vmlinux(s->module->name) ?"":".ko"); 198 } 199 } 200 s->preloaded = 0; 201 s->vmlinux = is_vmlinux(mod->name); 202 s->kernel = 0; 203 return s; 204 } 205 206 static void sym_update_crc(const char *name, struct module *mod, 207 unsigned int crc) 208 { 209 struct symbol *s = find_symbol(name); 210 211 if (!s) 212 s = new_symbol(name, mod); 213 s->crc = crc; 214 s->crc_valid = 1; 215 } 216 217 void *grab_file(const char *filename, unsigned long *size) 218 { 219 struct stat st; 220 void *map; 221 int fd; 222 223 fd = open(filename, O_RDONLY); 224 if (fd < 0 || fstat(fd, &st) != 0) 225 return NULL; 226 227 *size = st.st_size; 228 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 229 close(fd); 230 231 if (map == MAP_FAILED) 232 return NULL; 233 return map; 234 } 235 236 /** 237 * Return a copy of the next line in a mmap'ed file. 238 * spaces in the beginning of the line is trimmed away. 239 * Return a pointer to a static buffer. 240 **/ 241 char* get_next_line(unsigned long *pos, void *file, unsigned long size) 242 { 243 static char line[4096]; 244 int skip = 1; 245 size_t len = 0; 246 signed char *p = (signed char *)file + *pos; 247 char *s = line; 248 249 for (; *pos < size ; (*pos)++) 250 { 251 if (skip && isspace(*p)) { 252 p++; 253 continue; 254 } 255 skip = 0; 256 if (*p != '\n' && (*pos < size)) { 257 len++; 258 *s++ = *p++; 259 if (len > 4095) 260 break; /* Too long, stop */ 261 } else { 262 /* End of string */ 263 *s = '\0'; 264 return line; 265 } 266 } 267 /* End of buffer */ 268 return NULL; 269 } 270 271 void release_file(void *file, unsigned long size) 272 { 273 munmap(file, size); 274 } 275 276 static void parse_elf(struct elf_info *info, const char *filename) 277 { 278 unsigned int i; 279 Elf_Ehdr *hdr = info->hdr; 280 Elf_Shdr *sechdrs; 281 Elf_Sym *sym; 282 283 hdr = grab_file(filename, &info->size); 284 if (!hdr) { 285 perror(filename); 286 abort(); 287 } 288 info->hdr = hdr; 289 if (info->size < sizeof(*hdr)) 290 goto truncated; 291 292 /* Fix endianness in ELF header */ 293 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 294 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 295 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 296 hdr->e_machine = TO_NATIVE(hdr->e_machine); 297 sechdrs = (void *)hdr + hdr->e_shoff; 298 info->sechdrs = sechdrs; 299 300 /* Fix endianness in section headers */ 301 for (i = 0; i < hdr->e_shnum; i++) { 302 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 303 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 304 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 305 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 306 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 307 } 308 /* Find symbol table. */ 309 for (i = 1; i < hdr->e_shnum; i++) { 310 const char *secstrings 311 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 312 313 if (sechdrs[i].sh_offset > info->size) 314 goto truncated; 315 if (strcmp(secstrings+sechdrs[i].sh_name, ".modinfo") == 0) { 316 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 317 info->modinfo_len = sechdrs[i].sh_size; 318 } 319 if (sechdrs[i].sh_type != SHT_SYMTAB) 320 continue; 321 322 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; 323 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset 324 + sechdrs[i].sh_size; 325 info->strtab = (void *)hdr + 326 sechdrs[sechdrs[i].sh_link].sh_offset; 327 } 328 if (!info->symtab_start) { 329 fatal("%s has no symtab?\n", filename); 330 } 331 /* Fix endianness in symbols */ 332 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 333 sym->st_shndx = TO_NATIVE(sym->st_shndx); 334 sym->st_name = TO_NATIVE(sym->st_name); 335 sym->st_value = TO_NATIVE(sym->st_value); 336 sym->st_size = TO_NATIVE(sym->st_size); 337 } 338 return; 339 340 truncated: 341 fatal("%s is truncated.\n", filename); 342 } 343 344 static void parse_elf_finish(struct elf_info *info) 345 { 346 release_file(info->hdr, info->size); 347 } 348 349 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" 350 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" 351 352 static void handle_modversions(struct module *mod, struct elf_info *info, 353 Elf_Sym *sym, const char *symname) 354 { 355 unsigned int crc; 356 357 switch (sym->st_shndx) { 358 case SHN_COMMON: 359 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 360 break; 361 case SHN_ABS: 362 /* CRC'd symbol */ 363 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { 364 crc = (unsigned int) sym->st_value; 365 sym_update_crc(symname + strlen(CRC_PFX), mod, crc); 366 } 367 break; 368 case SHN_UNDEF: 369 /* undefined symbol */ 370 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 371 ELF_ST_BIND(sym->st_info) != STB_WEAK) 372 break; 373 /* ignore global offset table */ 374 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 375 break; 376 /* ignore __this_module, it will be resolved shortly */ 377 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) 378 break; 379 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 380 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 381 /* add compatibility with older glibc */ 382 #ifndef STT_SPARC_REGISTER 383 #define STT_SPARC_REGISTER STT_REGISTER 384 #endif 385 if (info->hdr->e_machine == EM_SPARC || 386 info->hdr->e_machine == EM_SPARCV9) { 387 /* Ignore register directives. */ 388 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 389 break; 390 if (symname[0] == '.') { 391 char *munged = strdup(symname); 392 munged[0] = '_'; 393 munged[1] = toupper(munged[1]); 394 symname = munged; 395 } 396 } 397 #endif 398 399 if (memcmp(symname, MODULE_SYMBOL_PREFIX, 400 strlen(MODULE_SYMBOL_PREFIX)) == 0) 401 mod->unres = alloc_symbol(symname + 402 strlen(MODULE_SYMBOL_PREFIX), 403 ELF_ST_BIND(sym->st_info) == STB_WEAK, 404 mod->unres); 405 break; 406 default: 407 /* All exported symbols */ 408 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { 409 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod); 410 } 411 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) 412 mod->has_init = 1; 413 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) 414 mod->has_cleanup = 1; 415 break; 416 } 417 } 418 419 /** 420 * Parse tag=value strings from .modinfo section 421 **/ 422 static char *next_string(char *string, unsigned long *secsize) 423 { 424 /* Skip non-zero chars */ 425 while (string[0]) { 426 string++; 427 if ((*secsize)-- <= 1) 428 return NULL; 429 } 430 431 /* Skip any zero padding. */ 432 while (!string[0]) { 433 string++; 434 if ((*secsize)-- <= 1) 435 return NULL; 436 } 437 return string; 438 } 439 440 static char *get_modinfo(void *modinfo, unsigned long modinfo_len, 441 const char *tag) 442 { 443 char *p; 444 unsigned int taglen = strlen(tag); 445 unsigned long size = modinfo_len; 446 447 for (p = modinfo; p; p = next_string(p, &size)) { 448 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 449 return p + taglen + 1; 450 } 451 return NULL; 452 } 453 454 /** 455 * Test if string s ends in string sub 456 * return 0 if match 457 **/ 458 static int strrcmp(const char *s, const char *sub) 459 { 460 int slen, sublen; 461 462 if (!s || !sub) 463 return 1; 464 465 slen = strlen(s); 466 sublen = strlen(sub); 467 468 if ((slen == 0) || (sublen == 0)) 469 return 1; 470 471 if (sublen > slen) 472 return 1; 473 474 return memcmp(s + slen - sublen, sub, sublen); 475 } 476 477 /** 478 * Whitelist to allow certain references to pass with no warning. 479 * Pattern 1: 480 * If a module parameter is declared __initdata and permissions=0 481 * then this is legal despite the warning generated. 482 * We cannot see value of permissions here, so just ignore 483 * this pattern. 484 * The pattern is identified by: 485 * tosec = .init.data 486 * fromsec = .data* 487 * atsym =__param* 488 * 489 * Pattern 2: 490 * Many drivers utilise a *_driver container with references to 491 * add, remove, probe functions etc. 492 * These functions may often be marked __init and we do not want to 493 * warn here. 494 * the pattern is identified by: 495 * tosec = .init.text | .exit.text 496 * fromsec = .data 497 * atsym = *_driver, *_ops, *_probe, *probe_one 498 **/ 499 static int secref_whitelist(const char *tosec, const char *fromsec, 500 const char *atsym) 501 { 502 int f1 = 1, f2 = 1; 503 const char **s; 504 const char *pat2sym[] = { 505 "_driver", 506 "_ops", 507 "_probe", 508 "_probe_one", 509 NULL 510 }; 511 512 /* Check for pattern 1 */ 513 if (strcmp(tosec, ".init.data") != 0) 514 f1 = 0; 515 if (strncmp(fromsec, ".data", strlen(".data")) != 0) 516 f1 = 0; 517 if (strncmp(atsym, "__param", strlen("__param")) != 0) 518 f1 = 0; 519 520 if (f1) 521 return f1; 522 523 /* Check for pattern 2 */ 524 if ((strcmp(tosec, ".init.text") != 0) && 525 (strcmp(tosec, ".exit.text") != 0)) 526 f2 = 0; 527 if (strcmp(fromsec, ".data") != 0) 528 f2 = 0; 529 530 for (s = pat2sym; *s; s++) 531 if (strrcmp(atsym, *s) == 0) 532 f1 = 1; 533 534 return f1 && f2; 535 } 536 537 /** 538 * Find symbol based on relocation record info. 539 * In some cases the symbol supplied is a valid symbol so 540 * return refsym. If st_name != 0 we assume this is a valid symbol. 541 * In other cases the symbol needs to be looked up in the symbol table 542 * based on section and address. 543 * **/ 544 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, 545 Elf_Sym *relsym) 546 { 547 Elf_Sym *sym; 548 549 if (relsym->st_name != 0) 550 return relsym; 551 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 552 if (sym->st_shndx != relsym->st_shndx) 553 continue; 554 if (sym->st_value == addr) 555 return sym; 556 } 557 return NULL; 558 } 559 560 /* 561 * Find symbols before or equal addr and after addr - in the section sec. 562 * If we find two symbols with equal offset prefer one with a valid name. 563 * The ELF format may have a better way to detect what type of symbol 564 * it is, but this works for now. 565 **/ 566 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr, 567 const char *sec, 568 Elf_Sym **before, Elf_Sym **after) 569 { 570 Elf_Sym *sym; 571 Elf_Ehdr *hdr = elf->hdr; 572 Elf_Addr beforediff = ~0; 573 Elf_Addr afterdiff = ~0; 574 const char *secstrings = (void *)hdr + 575 elf->sechdrs[hdr->e_shstrndx].sh_offset; 576 577 *before = NULL; 578 *after = NULL; 579 580 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 581 const char *symsec; 582 583 if (sym->st_shndx >= SHN_LORESERVE) 584 continue; 585 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name; 586 if (strcmp(symsec, sec) != 0) 587 continue; 588 if (sym->st_value <= addr) { 589 if ((addr - sym->st_value) < beforediff) { 590 beforediff = addr - sym->st_value; 591 *before = sym; 592 } 593 else if ((addr - sym->st_value) == beforediff) { 594 /* equal offset, valid name? */ 595 const char *name = elf->strtab + sym->st_name; 596 if (name && strlen(name)) 597 *before = sym; 598 } 599 } 600 else 601 { 602 if ((sym->st_value - addr) < afterdiff) { 603 afterdiff = sym->st_value - addr; 604 *after = sym; 605 } 606 else if ((sym->st_value - addr) == afterdiff) { 607 /* equal offset, valid name? */ 608 const char *name = elf->strtab + sym->st_name; 609 if (name && strlen(name)) 610 *after = sym; 611 } 612 } 613 } 614 } 615 616 /** 617 * Print a warning about a section mismatch. 618 * Try to find symbols near it so user can find it. 619 * Check whitelist before warning - it may be a false positive. 620 **/ 621 static void warn_sec_mismatch(const char *modname, const char *fromsec, 622 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r) 623 { 624 const char *refsymname = ""; 625 Elf_Sym *before, *after; 626 Elf_Sym *refsym; 627 Elf_Ehdr *hdr = elf->hdr; 628 Elf_Shdr *sechdrs = elf->sechdrs; 629 const char *secstrings = (void *)hdr + 630 sechdrs[hdr->e_shstrndx].sh_offset; 631 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name; 632 633 find_symbols_between(elf, r.r_offset, fromsec, &before, &after); 634 635 refsym = find_elf_symbol(elf, r.r_addend, sym); 636 if (refsym && strlen(elf->strtab + refsym->st_name)) 637 refsymname = elf->strtab + refsym->st_name; 638 639 /* check whitelist - we may ignore it */ 640 if (before && 641 secref_whitelist(secname, fromsec, elf->strtab + before->st_name)) 642 return; 643 644 if (before && after) { 645 warn("%s - Section mismatch: reference to %s:%s from %s " 646 "between '%s' (at offset 0x%llx) and '%s'\n", 647 modname, secname, refsymname, fromsec, 648 elf->strtab + before->st_name, 649 (long long)r.r_offset, 650 elf->strtab + after->st_name); 651 } else if (before) { 652 warn("%s - Section mismatch: reference to %s:%s from %s " 653 "after '%s' (at offset 0x%llx)\n", 654 modname, secname, refsymname, fromsec, 655 elf->strtab + before->st_name, 656 (long long)r.r_offset); 657 } else if (after) { 658 warn("%s - Section mismatch: reference to %s:%s from %s " 659 "before '%s' (at offset -0x%llx)\n", 660 modname, secname, refsymname, fromsec, 661 elf->strtab + before->st_name, 662 (long long)r.r_offset); 663 } else { 664 warn("%s - Section mismatch: reference to %s:%s from %s " 665 "(offset 0x%llx)\n", 666 modname, secname, fromsec, refsymname, 667 (long long)r.r_offset); 668 } 669 } 670 671 /** 672 * A module includes a number of sections that are discarded 673 * either when loaded or when used as built-in. 674 * For loaded modules all functions marked __init and all data 675 * marked __initdata will be discarded when the module has been intialized. 676 * Likewise for modules used built-in the sections marked __exit 677 * are discarded because __exit marked function are supposed to be called 678 * only when a moduel is unloaded which never happes for built-in modules. 679 * The check_sec_ref() function traverses all relocation records 680 * to find all references to a section that reference a section that will 681 * be discarded and warns about it. 682 **/ 683 static void check_sec_ref(struct module *mod, const char *modname, 684 struct elf_info *elf, 685 int section(const char*), 686 int section_ref_ok(const char *)) 687 { 688 int i; 689 Elf_Sym *sym; 690 Elf_Ehdr *hdr = elf->hdr; 691 Elf_Shdr *sechdrs = elf->sechdrs; 692 const char *secstrings = (void *)hdr + 693 sechdrs[hdr->e_shstrndx].sh_offset; 694 695 /* Walk through all sections */ 696 for (i = 0; i < hdr->e_shnum; i++) { 697 Elf_Rela *rela; 698 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset; 699 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size; 700 const char *name = secstrings + sechdrs[i].sh_name + 701 strlen(".rela"); 702 /* We want to process only relocation sections and not .init */ 703 if (section_ref_ok(name) || (sechdrs[i].sh_type != SHT_RELA)) 704 continue; 705 706 for (rela = start; rela < stop; rela++) { 707 Elf_Rela r; 708 const char *secname; 709 r.r_offset = TO_NATIVE(rela->r_offset); 710 r.r_info = TO_NATIVE(rela->r_info); 711 r.r_addend = TO_NATIVE(rela->r_addend); 712 sym = elf->symtab_start + ELF_R_SYM(r.r_info); 713 /* Skip special sections */ 714 if (sym->st_shndx >= SHN_LORESERVE) 715 continue; 716 717 secname = secstrings + sechdrs[sym->st_shndx].sh_name; 718 if (section(secname)) 719 warn_sec_mismatch(modname, name, elf, sym, r); 720 } 721 } 722 } 723 724 /** 725 * Functions used only during module init is marked __init and is stored in 726 * a .init.text section. Likewise data is marked __initdata and stored in 727 * a .init.data section. 728 * If this section is one of these sections return 1 729 * See include/linux/init.h for the details 730 **/ 731 static int init_section(const char *name) 732 { 733 if (strcmp(name, ".init") == 0) 734 return 1; 735 if (strncmp(name, ".init.", strlen(".init.")) == 0) 736 return 1; 737 return 0; 738 } 739 740 /** 741 * Identify sections from which references to a .init section is OK. 742 * 743 * Unfortunately references to read only data that referenced .init 744 * sections had to be excluded. Almost all of these are false 745 * positives, they are created by gcc. The downside of excluding rodata 746 * is that there really are some user references from rodata to 747 * init code, e.g. drivers/video/vgacon.c: 748 * 749 * const struct consw vga_con = { 750 * con_startup: vgacon_startup, 751 * 752 * where vgacon_startup is __init. If you want to wade through the false 753 * positives, take out the check for rodata. 754 **/ 755 static int init_section_ref_ok(const char *name) 756 { 757 const char **s; 758 /* Absolute section names */ 759 const char *namelist1[] = { 760 ".init", 761 ".opd", /* see comment [OPD] at exit_section_ref_ok() */ 762 ".toc1", /* used by ppc64 */ 763 ".stab", 764 ".rodata", 765 ".text.lock", 766 "__bug_table", /* used by powerpc for BUG() */ 767 ".pci_fixup_header", 768 ".pci_fixup_final", 769 ".pdr", 770 "__param", 771 NULL 772 }; 773 /* Start of section names */ 774 const char *namelist2[] = { 775 ".init.", 776 ".altinstructions", 777 ".eh_frame", 778 ".debug", 779 NULL 780 }; 781 /* part of section name */ 782 const char *namelist3 [] = { 783 ".unwind", /* sample: IA_64.unwind.init.text */ 784 NULL 785 }; 786 787 for (s = namelist1; *s; s++) 788 if (strcmp(*s, name) == 0) 789 return 1; 790 for (s = namelist2; *s; s++) 791 if (strncmp(*s, name, strlen(*s)) == 0) 792 return 1; 793 for (s = namelist3; *s; s++) 794 if (strstr(name, *s) != NULL) 795 return 1; 796 return 0; 797 } 798 799 /* 800 * Functions used only during module exit is marked __exit and is stored in 801 * a .exit.text section. Likewise data is marked __exitdata and stored in 802 * a .exit.data section. 803 * If this section is one of these sections return 1 804 * See include/linux/init.h for the details 805 **/ 806 static int exit_section(const char *name) 807 { 808 if (strcmp(name, ".exit.text") == 0) 809 return 1; 810 if (strcmp(name, ".exit.data") == 0) 811 return 1; 812 return 0; 813 814 } 815 816 /* 817 * Identify sections from which references to a .exit section is OK. 818 * 819 * [OPD] Keith Ownes <kaos@sgi.com> commented: 820 * For our future {in}sanity, add a comment that this is the ppc .opd 821 * section, not the ia64 .opd section. 822 * ia64 .opd should not point to discarded sections. 823 **/ 824 static int exit_section_ref_ok(const char *name) 825 { 826 const char **s; 827 /* Absolute section names */ 828 const char *namelist1[] = { 829 ".exit.text", 830 ".exit.data", 831 ".init.text", 832 ".opd", /* See comment [OPD] */ 833 ".toc1", /* used by ppc64 */ 834 ".altinstructions", 835 ".pdr", 836 "__bug_table", /* used by powerpc for BUG() */ 837 ".exitcall.exit", 838 ".eh_frame", 839 ".stab", 840 NULL 841 }; 842 /* Start of section names */ 843 const char *namelist2[] = { 844 ".debug", 845 NULL 846 }; 847 /* part of section name */ 848 const char *namelist3 [] = { 849 ".unwind", /* Sample: IA_64.unwind.exit.text */ 850 NULL 851 }; 852 853 for (s = namelist1; *s; s++) 854 if (strcmp(*s, name) == 0) 855 return 1; 856 for (s = namelist2; *s; s++) 857 if (strncmp(*s, name, strlen(*s)) == 0) 858 return 1; 859 for (s = namelist3; *s; s++) 860 if (strstr(name, *s) != NULL) 861 return 1; 862 return 0; 863 } 864 865 static void read_symbols(char *modname) 866 { 867 const char *symname; 868 char *version; 869 struct module *mod; 870 struct elf_info info = { }; 871 Elf_Sym *sym; 872 873 parse_elf(&info, modname); 874 875 mod = new_module(modname); 876 877 /* When there's no vmlinux, don't print warnings about 878 * unresolved symbols (since there'll be too many ;) */ 879 if (is_vmlinux(modname)) { 880 have_vmlinux = 1; 881 mod->skip = 1; 882 } 883 884 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 885 symname = info.strtab + sym->st_name; 886 887 handle_modversions(mod, &info, sym, symname); 888 handle_moddevtable(mod, &info, sym, symname); 889 } 890 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok); 891 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok); 892 893 version = get_modinfo(info.modinfo, info.modinfo_len, "version"); 894 if (version) 895 maybe_frob_rcs_version(modname, version, info.modinfo, 896 version - (char *)info.hdr); 897 if (version || (all_versions && !is_vmlinux(modname))) 898 get_src_version(modname, mod->srcversion, 899 sizeof(mod->srcversion)-1); 900 901 parse_elf_finish(&info); 902 903 /* Our trick to get versioning for struct_module - it's 904 * never passed as an argument to an exported function, so 905 * the automatic versioning doesn't pick it up, but it's really 906 * important anyhow */ 907 if (modversions) 908 mod->unres = alloc_symbol("struct_module", 0, mod->unres); 909 } 910 911 #define SZ 500 912 913 /* We first write the generated file into memory using the 914 * following helper, then compare to the file on disk and 915 * only update the later if anything changed */ 916 917 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 918 const char *fmt, ...) 919 { 920 char tmp[SZ]; 921 int len; 922 va_list ap; 923 924 va_start(ap, fmt); 925 len = vsnprintf(tmp, SZ, fmt, ap); 926 buf_write(buf, tmp, len); 927 va_end(ap); 928 } 929 930 void buf_write(struct buffer *buf, const char *s, int len) 931 { 932 if (buf->size - buf->pos < len) { 933 buf->size += len + SZ; 934 buf->p = realloc(buf->p, buf->size); 935 } 936 strncpy(buf->p + buf->pos, s, len); 937 buf->pos += len; 938 } 939 940 /** 941 * Header for the generated file 942 **/ 943 static void add_header(struct buffer *b, struct module *mod) 944 { 945 buf_printf(b, "#include <linux/module.h>\n"); 946 buf_printf(b, "#include <linux/vermagic.h>\n"); 947 buf_printf(b, "#include <linux/compiler.h>\n"); 948 buf_printf(b, "\n"); 949 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 950 buf_printf(b, "\n"); 951 buf_printf(b, "struct module __this_module\n"); 952 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 953 buf_printf(b, " .name = KBUILD_MODNAME,\n"); 954 if (mod->has_init) 955 buf_printf(b, " .init = init_module,\n"); 956 if (mod->has_cleanup) 957 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 958 " .exit = cleanup_module,\n" 959 "#endif\n"); 960 buf_printf(b, "};\n"); 961 } 962 963 /** 964 * Record CRCs for unresolved symbols 965 **/ 966 static void add_versions(struct buffer *b, struct module *mod) 967 { 968 struct symbol *s, *exp; 969 970 for (s = mod->unres; s; s = s->next) { 971 exp = find_symbol(s->name); 972 if (!exp || exp->module == mod) { 973 if (have_vmlinux && !s->weak) 974 warn("\"%s\" [%s.ko] undefined!\n", 975 s->name, mod->name); 976 continue; 977 } 978 s->module = exp->module; 979 s->crc_valid = exp->crc_valid; 980 s->crc = exp->crc; 981 } 982 983 if (!modversions) 984 return; 985 986 buf_printf(b, "\n"); 987 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 988 buf_printf(b, "__attribute_used__\n"); 989 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 990 991 for (s = mod->unres; s; s = s->next) { 992 if (!s->module) { 993 continue; 994 } 995 if (!s->crc_valid) { 996 warn("\"%s\" [%s.ko] has no CRC!\n", 997 s->name, mod->name); 998 continue; 999 } 1000 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); 1001 } 1002 1003 buf_printf(b, "};\n"); 1004 } 1005 1006 static void add_depends(struct buffer *b, struct module *mod, 1007 struct module *modules) 1008 { 1009 struct symbol *s; 1010 struct module *m; 1011 int first = 1; 1012 1013 for (m = modules; m; m = m->next) { 1014 m->seen = is_vmlinux(m->name); 1015 } 1016 1017 buf_printf(b, "\n"); 1018 buf_printf(b, "static const char __module_depends[]\n"); 1019 buf_printf(b, "__attribute_used__\n"); 1020 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 1021 buf_printf(b, "\"depends="); 1022 for (s = mod->unres; s; s = s->next) { 1023 if (!s->module) 1024 continue; 1025 1026 if (s->module->seen) 1027 continue; 1028 1029 s->module->seen = 1; 1030 buf_printf(b, "%s%s", first ? "" : ",", 1031 strrchr(s->module->name, '/') + 1); 1032 first = 0; 1033 } 1034 buf_printf(b, "\";\n"); 1035 } 1036 1037 static void add_srcversion(struct buffer *b, struct module *mod) 1038 { 1039 if (mod->srcversion[0]) { 1040 buf_printf(b, "\n"); 1041 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 1042 mod->srcversion); 1043 } 1044 } 1045 1046 static void write_if_changed(struct buffer *b, const char *fname) 1047 { 1048 char *tmp; 1049 FILE *file; 1050 struct stat st; 1051 1052 file = fopen(fname, "r"); 1053 if (!file) 1054 goto write; 1055 1056 if (fstat(fileno(file), &st) < 0) 1057 goto close_write; 1058 1059 if (st.st_size != b->pos) 1060 goto close_write; 1061 1062 tmp = NOFAIL(malloc(b->pos)); 1063 if (fread(tmp, 1, b->pos, file) != b->pos) 1064 goto free_write; 1065 1066 if (memcmp(tmp, b->p, b->pos) != 0) 1067 goto free_write; 1068 1069 free(tmp); 1070 fclose(file); 1071 return; 1072 1073 free_write: 1074 free(tmp); 1075 close_write: 1076 fclose(file); 1077 write: 1078 file = fopen(fname, "w"); 1079 if (!file) { 1080 perror(fname); 1081 exit(1); 1082 } 1083 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 1084 perror(fname); 1085 exit(1); 1086 } 1087 fclose(file); 1088 } 1089 1090 static void read_dump(const char *fname, unsigned int kernel) 1091 { 1092 unsigned long size, pos = 0; 1093 void *file = grab_file(fname, &size); 1094 char *line; 1095 1096 if (!file) 1097 /* No symbol versions, silently ignore */ 1098 return; 1099 1100 while ((line = get_next_line(&pos, file, size))) { 1101 char *symname, *modname, *d; 1102 unsigned int crc; 1103 struct module *mod; 1104 struct symbol *s; 1105 1106 if (!(symname = strchr(line, '\t'))) 1107 goto fail; 1108 *symname++ = '\0'; 1109 if (!(modname = strchr(symname, '\t'))) 1110 goto fail; 1111 *modname++ = '\0'; 1112 if (strchr(modname, '\t')) 1113 goto fail; 1114 crc = strtoul(line, &d, 16); 1115 if (*symname == '\0' || *modname == '\0' || *d != '\0') 1116 goto fail; 1117 1118 if (!(mod = find_module(modname))) { 1119 if (is_vmlinux(modname)) { 1120 have_vmlinux = 1; 1121 } 1122 mod = new_module(NOFAIL(strdup(modname))); 1123 mod->skip = 1; 1124 } 1125 s = sym_add_exported(symname, mod); 1126 s->kernel = kernel; 1127 s->preloaded = 1; 1128 sym_update_crc(symname, mod, crc); 1129 } 1130 return; 1131 fail: 1132 fatal("parse error in symbol dump file\n"); 1133 } 1134 1135 /* For normal builds always dump all symbols. 1136 * For external modules only dump symbols 1137 * that are not read from kernel Module.symvers. 1138 **/ 1139 static int dump_sym(struct symbol *sym) 1140 { 1141 if (!external_module) 1142 return 1; 1143 if (sym->vmlinux || sym->kernel) 1144 return 0; 1145 return 1; 1146 } 1147 1148 static void write_dump(const char *fname) 1149 { 1150 struct buffer buf = { }; 1151 struct symbol *symbol; 1152 int n; 1153 1154 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 1155 symbol = symbolhash[n]; 1156 while (symbol) { 1157 if (dump_sym(symbol)) 1158 buf_printf(&buf, "0x%08x\t%s\t%s\n", 1159 symbol->crc, symbol->name, 1160 symbol->module->name); 1161 symbol = symbol->next; 1162 } 1163 } 1164 write_if_changed(&buf, fname); 1165 } 1166 1167 int main(int argc, char **argv) 1168 { 1169 struct module *mod; 1170 struct buffer buf = { }; 1171 char fname[SZ]; 1172 char *kernel_read = NULL, *module_read = NULL; 1173 char *dump_write = NULL; 1174 int opt; 1175 1176 while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) { 1177 switch(opt) { 1178 case 'i': 1179 kernel_read = optarg; 1180 break; 1181 case 'I': 1182 module_read = optarg; 1183 external_module = 1; 1184 break; 1185 case 'm': 1186 modversions = 1; 1187 break; 1188 case 'o': 1189 dump_write = optarg; 1190 break; 1191 case 'a': 1192 all_versions = 1; 1193 break; 1194 default: 1195 exit(1); 1196 } 1197 } 1198 1199 if (kernel_read) 1200 read_dump(kernel_read, 1); 1201 if (module_read) 1202 read_dump(module_read, 0); 1203 1204 while (optind < argc) { 1205 read_symbols(argv[optind++]); 1206 } 1207 1208 for (mod = modules; mod; mod = mod->next) { 1209 if (mod->skip) 1210 continue; 1211 1212 buf.pos = 0; 1213 1214 add_header(&buf, mod); 1215 add_versions(&buf, mod); 1216 add_depends(&buf, mod, modules); 1217 add_moddevtable(&buf, mod); 1218 add_srcversion(&buf, mod); 1219 1220 sprintf(fname, "%s.mod.c", mod->name); 1221 write_if_changed(&buf, fname); 1222 } 1223 1224 if (dump_write) 1225 write_dump(dump_write); 1226 1227 return 0; 1228 } 1229